Japanese Patent Application Publication No. 2001-321970 discloses a laser marking device in which generated is a plurality of pieces of coordinate data representing coordinate points including start points and end points of line segments that make up of print design to be formed by laser processing. A laser is successively irradiated onto a series of coordinate points on a point-to-point basis starting from the start point and ending at the end point of the straight line segment. Each of a plurality of straight line segments is laser scanned in such a way, so that the print design, such as a character string, is formed on a workpiece.
With the laser marking device disclosed in Japanese Patent Application Publication No. 2001-321970, two adjacent coordinate points are generated to be apart a long distance one from the other and the line between the that the print quality is not degraded, a total amount of coordinate data is decreased, and a high speed printing can be achieved without being affected by a data transfer limitation.
On the other hand, it is unlikely that the tracking delay of the Galvano-mirror occurs when the print speed is set low, and thus it is capable of precisely forming a print design on a workpiece. Generating coordinate data for a straight line segment with a short point-to-point distance results in high density in the number of coordinate points, thereby enabling a smoothly curving line to print. While a total amount of transfer data increases, data transfer can be accomplished because the print speed is not as high as the data transfer speed.
A set of two points is scanned at a fast speed. The longer the point-to-point distance is in the straight line segment, the faster the scanning speed is set. As such, tracking delay of a Galvano-mirror occurs as the print speed gets faster. When two straight line segments are connected to be in diagonal relation, the laser beam smoothly scans along a curve line, rather than a bent line forming an angle between two straight lines.
As described, according to the laser marking device disclosed in Japanese Patent Application Publication No. 2001-321970, the higher the scanning speed of the Galvano-mirror is set to, the longer the point-to-point distance between the two adjacent coordinate points on the straight line segment is set. Hence, a high speed printing can be carried out without being affected by the data transfer limitation.